The invention relates to a method and a device for heating the pressure belt of a press, wherein the press pressure is exerted on the working run of the pressure belt by a gas-filled pressure chamber, and the heat transfer is increased by a high circulation rate of the pressure medium in the pressure chamber.
A method of this type is known (DE-OS 37 19 976) in which the pressure is generated by a fluid pressure medium in a pressure chamber, said chamber being sealed all the way around and delimited on one side by a pressure plate and on the other side by the pressure belt of a press, especially a double-belt press, said pressure medium being movable by force. The pressure medium is moved in turbulent fashion in the operating zone in a short circuit between the internally heated pressure plate and the back of the pressure belt, at flow rates of 2 to 50 m/sec, preferably 20 to 40 m/sec in the case of gaseous pressure media.
In this known method, the degree of heat transfer capability of the pressure medium can be controlled by varying the flow rate and/or the operating pressure. The heat transfer capability of the pressure medium is increased by a higher flow rate and/or an increased operating pressure.
In the case of materials for whose compression and/or curing a relatively low pressure is created in the pressure chamber, the circulation rate of the pressure medium must be sharply increased accordingly, resulting in increased energy consumption. In addition, the quantity of heat transferable by the known method is not sufficient for certain tasks.